Synthetic Methods Driven by the Photoactivity of Electron Donor–Acceptor Complexes

Journal of the American Chemical Society, Год журнала: 2020, Номер 142(12), С. 5461 - 5476

Опубликована: Март 5, 2020

The association of an electron-rich substrate with electron-accepting molecule can generate a new molecular aggregate in the ground state, called electron donor-acceptor (EDA) complex. Even when two precursors do not absorb visible light, resulting EDA complex often does. In 1952, Mulliken proposed quantum-mechanical theory to rationalize formation such colored complexes. However, and besides few pioneering studies 20th century, it is only past years that photochemistry has been recognized as powerful strategy for expanding potential visible-light-driven radical synthetic chemistry. Here, we explain why this photochemical approach was overlooked so long. We critically discuss historical context, scientific reasons, serendipitous observations, landmark discoveries were essential progress field. also outline future directions identify key advances are needed fully exploit photochemistry.

Язык: Английский

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Photocatalytic decarboxylative alkylations mediated by triphenylphosphine and sodium iodide

Science, Год журнала: 2019, Номер 363(6434), С. 1429 - 1434

Опубликована: Март 28, 2019

Most photoredox catalysts in current use are precious metal complexes or synthetically elaborate organic dyes, the cost of which can impede their application for large-scale industrial processes. We found that a combination triphenylphosphine and sodium iodide under 456-nanometer irradiation by blue light-emitting diodes catalyze alkylation silyl enol ethers decarboxylative coupling with redox-active esters absence transition metals. Deaminative using Katritzky's N-alkylpyridinium salts trifluoromethylation Togni's reagent also demonstrated. Moreover, phosphine/iodide-based system catalyzes Minisci-type N-heterocycles operate tandem chiral phosphoric acids to achieve high enantioselectivity this reaction.

Язык: Английский

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Visible light photocatalysis in the late-stage functionalization of pharmaceutically relevant compounds

Chemical Society Reviews, Год журнала: 2020, Номер 50(2), С. 766 - 897

Опубликована: Дек. 22, 2020

Recent developments and future prospects of visible-light photocatalysis in the late-stage functionalization pharmaceuticals natural bioactive compounds.

Язык: Английский

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Photocatalytic Late-Stage C–H Functionalization

Chemical Reviews, Год журнала: 2023, Номер 123(8), С. 4237 - 4352

Опубликована: Янв. 24, 2023

The emergence of modern photocatalysis, characterized by mildness and selectivity, has significantly spurred innovative late-stage C–H functionalization approaches that make use low energy photons as a controllable source. Compared to traditional strategies, photocatalysis paves the way toward complementary and/or previously unattainable regio- chemoselectivities. Merging compelling benefits with workflow offers potentially unmatched arsenal tackle drug development campaigns beyond. This Review highlights photocatalytic strategies small-molecule drugs, agrochemicals, natural products, classified according targeted bond newly formed one. Emphasis is devoted identifying, describing, comparing main mechanistic scenarios. draws critical comparison between established ionic chemistry photocatalyzed radical-based manifolds. aims establish current state-of-the-art illustrate key unsolved challenges be addressed in future. authors aim introduce general readership functionalization, specialist practitioners evaluation methodologies, potential for improvement, future uncharted directions.

Язык: Английский

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Radical Carboxylative Cyclizations and Carboxylations with CO₂

Accounts of Chemical Research, Год журнала: 2021, Номер 54(10), С. 2518 - 2531

Опубликована: Май 6, 2021

ConspectusCarbon dioxide (CO2) is not only a greenhouse gas and common waste product but also an inexpensive, readily available, renewable carbon resource. It important one-carbon (C1) building block in organic synthesis for the construction of valuable compounds. However, its utilization challenging owing to thermodynamic stability kinetic inertness. Although significant progress has been achieved, many limitations remain this field with regard substrate scope, reaction system, activation strategies.Since 2015, our group focused on CO2 synthesis. We are interested vast possibilities radical chemistry, although high reactivity radicals presents challenges controlling selectivity. hope develop highly useful transformations involving by achieving balance selectivity under mild conditions. Over past 6 years, we along other experts have disclosed radical-type carboxylative cyclizations carboxylations using CO2.We initiated research realizing Cu-catalyzed oxytrifluoromethylation allylamines heteroaryl methylamines generate 2-oxazolidones various precursors. Apart from Cu catalysis, visible-light photoredox catalysis powerful method achieve efficient cyclization. In these cases, single-electron-oxidation-promoted C–O bond formation between benzylic carbamates key step.Since carboxylic acids exist widely natural products bioactive drugs serve as bulk chemicals industry, realized further visible-light-promoted construct such chemicals. achieved selective umpolung imines, enamides, tetraalkylammonium salts, oxime esters successive single-electron-transfer (SSET) reduction. Using strategy, dearomative arylcarboxylation indoles CO2. addition incorporation 1 equiv per substrate, recently developed photoredox-catalyzed dicarboxylation alkenes, allenes, (hetero)arenes via SSET reduction, which allows two molecules into compounds diacids polymer precursors.In two-electron CO2, sought new strategies realize single-electron Inspired hypothetical electron-transfer mechanism iron–sulfur proteins, visible-light-driven thiocarboxylation alkenes catalytic iron salts promoters. The in-situ-generated Fe/S complexes likely able reduce anion, could react give stabilized radical. Moreover, charge-transfer complex (CTC) thiolate acrylate/styrene hydrocarboxylation generation or alkene anion. On basis novel CTC, organocatalytic Hantzsch ester effective reductant.

Язык: Английский

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Catalyst‐Free Deaminative Functionalizations of Primary Amines by Photoinduced Single‐Electron Transfer

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(17), С. 5697 - 5701

Опубликована: Фев. 22, 2019

Abstract The use of pyridinium‐activated primary amines as photoactive functional groups for deaminative generation alkyl radicals under catalyst‐free conditions is described. By taking advantage the visible light absorptivity electron donor–acceptor complexes between Katritzky pyridinium salts and either Hantzsch ester or Et 3 N, photoinduced single‐electron transfer could be initiated in absence a photocatalyst. This general reactivity platform has been applied to alkylation (Giese), allylation, vinylation, alkynylation, thioetherification, hydrodeamination reactions. mild are amenable diverse range secondary pyridiniums demonstrate broad group tolerance.

Язык: Английский

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Visible-Light-Driven Reductive Carboarylation of Styrenes with CO₂ and Aryl Halides

Journal of the American Chemical Society, Год журнала: 2020, Номер 142(18), С. 8122 - 8129

Опубликована: Апрель 20, 2020

The first example of visible-light-driven reductive carboarylation styrenes with CO2 and aryl halides in a regioselective manner has been achieved. A broad range iodides bromides were compatible this reaction. Moreover, pyridyl halides, alkyl even chlorides also viable method. These findings may stimulate the exploration novel Meerwein arylation-addition reactions user-friendly as radical sources photocatalytic utilization CO2.

Язык: Английский

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Deaminative Borylation of Aliphatic Amines Enabled by Visible Light Excitation of an Electron Donor–Acceptor Complex

Chemistry - A European Journal, Год журнала: 2018, Номер 24(65), С. 17210 - 17214

Опубликована: Окт. 6, 2018

Abstract A deaminative strategy for the borylation of aliphatic primary amines is described. Alkyl radicals derived from single‐electron reduction redox‐active pyridinium salts, which can be isolated or generated in situ, were borylated a visible light‐mediated reaction with bis(catecholato)diboron. No catalyst further additives required. The key electron donor–acceptor complex was characterized detail by both experimental and computational investigations. synthetic potential this mild protocol demonstrated through late‐stage functionalization natural products drug molecules.

Язык: Английский

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C–N Cross-Coupling via Photoexcitation of Nickel–Amine Complexes

Journal of the American Chemical Society, Год журнала: 2018, Номер 140(24), С. 7667 - 7673

Опубликована: Май 22, 2018

C-N cross-coupling is an important class of reactions with far-reaching impacts across chemistry, materials science, biology, and medicine. Transition metal complexes can elegantly orchestrate diverse aminations but typically require demanding reaction conditions, precious catalysts, or oxygen-sensitive procedures. Here, we introduce a mild nickel-catalyzed methodology that operates at room temperature using inexpensive nickel source (NiBr2·3H2O), oxygen tolerant, proceeds through direct irradiation the nickel-amine complex. This operationally robust process was employed for synthesis C-N-coupled products (40 examples) by irradiating solution containing amine, aryl halide, catalytic amount NiBr2·3H2O commercially available 365 nm LED without added photoredox catalyst amine substrate serving additional roles as ligands base. Density functional theory calculations kinetic isotope effect experiments were performed to elucidate observed reactivity.

Язык: Английский

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Recent advances in catalyst-free photochemical reactions via electron-donor-acceptor (EDA) complex process

Tetrahedron Letters, Год журнала: 2019, Номер 61(8), С. 151506 - 151506

Опубликована: Дек. 9, 2019

Язык: Английский

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